High-voltage cable white spot detection method and device, electronic equipment and storage medium

Abstract

The invention discloses a high-voltage cable white spot detection method and device, electronic equipment and a storage medium, and the method comprises the steps: building a circular thermal circuit model of a cable according to the structural parameters of the external structure of each layer of the cable, the circular thermal circuit model being the cross section of the cable, the cross section being divided into a plurality of fan-shaped infinitesimal elements, each fan-shaped infinitesimal element comprises a plurality of thermal resistance branches which extend from the conductor to the outer sheath, and each thermal resistance branch comprises structural thermal resistors which are in one-to-one correspondence with external structures; at least one thermal resistance branch also comprises a white spot thermal resistor; for each thermal resistance branch, calculating the thermal resistance value of the structural thermal resistor on each thermal resistance branch according to the radian and the structural parameter of the fan-shaped infinitesimal to which the thermal resistance branch belongs; measuring the surface temperature of the cable, the conductor temperature of the conductor and the load current value of the conductor corresponding to each thermal resistance branch; and calculating the thermal resistance value of the white spot thermal resistor according to the data, and determining whether the white spot exists and the position of the white spot. The white spots can be detected in the early stage of generating the white spots, and further expansion of the white spots is avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of power grid inspection and maintenance, and in particular to a method, device, electronic equipment and storage medium for detecting white spot on a high-voltage cable. Background Art

[0002] High-voltage cross-linked polyethylene cables have strong current-carrying capacity, good stability and wide application. However, as the operation time of high-voltage cables increases, buffer layer ablation failures will occur. Buffer layer ablation failures occur between the corrugated aluminum sheath of the high-voltage cable body and the outer semi-conductive shield (insulating layer), which is characterized by the formation of "white spots" on the buffer layer, the outer semi-conductive shield and the inner surface of the aluminum sheath. In order to solve the problem of white spots in the buffer layer after the corrugated aluminum sheath cable has been running for a certain period of time, cable manufacturers have begun to adopt smooth aluminum sheaths instead of corrugated aluminum sheaths and put them into operation. However, even with smooth aluminum sheaths, the existing cable manufacturers' improper degassing operations or insufficient degassing time will still lead to the generation of water vapor, and the potential difference is inevitable, and the buffer layer still has electrochemical corrosion and white spots. As the cable runs longer, the thickness of the white spots will continue to change due to the influence of the temperature and humidity of the laying environment, which will have a greater impact on the operating performance of the cable.

[0003] At present, the main method for detecting white spots is to detect the location of white spots through fault inspection (white spots cause cable line faults), but this will cause power outage losses, and is usually performed only after it is found that the white spot fault has greatly affected the stable operation of the cable. There is no research to provide a specific detection plan for whether there are white spots on cables that are operating normally. Moreover, most studies focus on the repair method of white spots and the detection of discharge performance after repair, and have not yet provided a method for determining the location of white spots. Summary of the invention

[0004] The invention provides a method for detecting white spots on a high-voltage cable, so as to solve the problem of detecting white spots on a high-voltage cable.

[0005] In a first aspect, the present invention provides a method for detecting white spots in a high-voltage cable. The cable structure includes a conductor and a three-layer external structure. The external structure includes an insulating layer, a buffer layer and an outer sheath from the inside to the outside. The cross-section of the external structure is annular. The method includes:

[0006] Acquire structural parameters of the external structure of each layer of the cable, wherein the structural parameters include the inner diameter and the outer diameter of the external structure;

[0007] A circular thermal circuit model of the cable is established according to the structural parameters, wherein the circular thermal circuit model is a cross section of the cable, wherein the cross section is divided into a plurality of sector-shaped microelements, each of the sector-shaped microelements includes a plurality of thermal resistance branches extending from the conductor to the outer sheath, each of the thermal resistance branches includes a structural thermal resistance corresponding to the external structure one by one; at least one of the thermal resistance branches also includes a white spot thermal resistance;

[0008] For each of the thermal resistance branches, the thermal resistance value of the structural thermal resistor on each of the thermal resistance branches is calculated according to the curvature of the sector-shaped microelement and the structural parameters;

[0009] Measuring the cable surface temperature, the conductor temperature of the conductor and the load current value of the conductor corresponding to each of the thermal resistance branches;

[0010] Calculate the heat flow of the entire cable according to the conductor temperature and the load current value;

[0011] Calculate the thermal resistance value of the white spot thermal resistance according to the thermal resistance value of the structural thermal resistance, the cable surface temperature, the conductor temperature and the heat flow of the entire cable;

[0012] Whether there are white spots and the location of the white spots when there are white spots are determined according to the thermal resistance value of the white spot thermal resistance.

[0013] In a second aspect, the present invention provides a high-voltage cable white spot detection device, the cable structure includes a conductor and a three-layer external structure, the external structure includes an insulating layer, a buffer layer and an outer sheath from the inside to the outside, the cross-section of the external structure is annular, and the device includes:

[0014] A structural parameter acquisition module, used to acquire structural parameters of the external structure of each layer of the cable, wherein the structural parameters include the inner diameter and the outer diameter of the external structure;

[0015] A thermal circuit model building module is used to establish a circular thermal circuit model of the cable according to the structural parameters, wherein the circular thermal circuit model is a cross section of the cable, wherein the cross section is divided into a plurality of sector-shaped micro-elements, each of which includes a plurality of thermal resistance branches extending from the conductor to the outer sheath, each of which includes a structural thermal resistance corresponding to the external structure one by one; and at least one of the thermal resistance branches also includes a white spot thermal resistance;

[0016] A thermal resistance value calculation module, used for calculating the thermal resistance value of the structural thermal resistor on each thermal resistance branch according to the curvature of the sector-shaped microelement and the structural parameters thereof for each thermal resistance branch;

[0017] A parameter measurement module, used to measure the cable surface temperature, the conductor temperature and the load current value of the conductor corresponding to each thermal resistance branch;

[0018] A cable full-line heat flow calculation module, used to calculate the cable full-line heat flow according to the conductor temperature and the load current value;

[0019] A white spot thermal resistance calculation module, used to calculate the thermal resistance value of the white spot thermal resistance according to the thermal resistance value of the structural thermal resistance, the cable surface temperature, the conductor temperature and the heat flow of the entire cable;

[0020] The white spot qualitative module is used to determine whether white spots exist and the location of the white spots when white spots exist according to the thermal resistance value of the white spot thermal resistance.

[0021] In a third aspect, the present invention provides an electronic device, the electronic device comprising:

[0022] at least one processor; and

[0023] a memory communicatively connected to the at least one processor; wherein,

[0024] The memory stores a computer program executable by the at least one processor, and the computer program is executed by the at least one processor so that the at least one processor can execute the high-voltage cable white spot detection method described in the first aspect of the present invention.

[0025] In a fourth aspect, the present invention provides a computer-readable storage medium, wherein the computer-readable storage medium stores computer instructions, and the computer instructions are used to implement the high-voltage cable white spot detection method described in the first aspect of the present invention when executed by a processor.

[0026] The method for detecting white spots in high-voltage cables provided by an embodiment of the present invention first obtains the structural parameters of the external structure of each layer of the cable, the structural parameters including the inner diameter and the outer diameter of the external structure; a circular thermal circuit model of the cable is established according to the structural parameters, the circular thermal circuit model is the cross section of the cable, the cross section is divided into a plurality of sector-shaped microelements, each sector-shaped microelement includes a plurality of thermal resistance branches extending from the conductor to the outer sheath, each thermal resistance branch includes a structural thermal resistance corresponding to the external structure one by one; at least one thermal resistance branch also includes a white spot thermal resistance; for each thermal resistance branch, the thermal resistance value of the structural thermal resistance on each thermal resistance branch is calculated according to the curvature and structural parameters of the sector-shaped microelement to which it belongs; the cable surface temperature, the conductor temperature of the conductor and the load current value of the conductor corresponding to each thermal resistance branch are measured; the heat flow of the entire cable is calculated according to the conductor temperature and the load current value, and the thermal resistance value of the white spot thermal resistance is calculated according to the thermal resistance value of the structural thermal resistance, the cable surface temperature, the conductor temperature and the heat flow of the entire cable; and whether white spots exist and the location of the white spots when white spots exist are determined according to the thermal resistance value of the white spot thermal resistance. Based on the thermal circuit model, the sector-shaped micro-element where the white spot is located is virtually constructed, and the parameters in each sector-shaped micro-element are measured and calculated. The thermal resistance value of the white spot is qualitatively calculated according to the Fourier heat transfer law combined with the thermal circuit model. Therefore, it is possible to determine whether there are white spots and the location of the white spots when they exist. The white spots can be detected in the early stage of their occurrence, and the filling of repair fluid can be used to repair the cable in time to prevent the white spots from further expanding and causing a greater impact on the cable's operating performance.

[0027] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present invention, nor are they intended to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0029] Figure 1 is a schematic diagram of a cross-sectional structure of a cable provided by an embodiment of the present invention;

[0030] Figure 2 is a flow chart of a high-voltage cable white spot detection method provided by an embodiment of the present invention;

[0031] Figure 3 is a schematic diagram of a circular heat path model provided by an embodiment of the present invention;

[0032] Figure 4It is a structural schematic diagram of a high-voltage cable white spot detection device provided by an embodiment of the present invention;

[0033] Figure 5 It is a schematic diagram of the structure of an electronic device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0034] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0035] The embodiment of the present invention provides a method for detecting white spots on a high-voltage cable. The embodiment can be applied to the case of detecting white spots on an insulating layer of a high-voltage cable. The method can be performed by a high-voltage cable white spot detection device. The high-voltage cable white spot detection device can be implemented in the form of hardware and / or software. The high-voltage cable white spot detection device can be configured in an electronic device. The cable in the present invention is a high-voltage cable.

[0036] Figure 1 A schematic diagram of a cross-sectional structure of a cable provided in an embodiment of the present invention, such as Figure 1 As shown, the structure of the cable includes a conductor A0 and a three-layer external structure. The external structure includes an insulating layer A1, a buffer layer A2 and an outer sheath A2 from the inside to the outside. The cross-section of the external structure is annular, and the cross-section of the conductor A1 is circular.

[0037] Figure 2 A flowchart of a high-voltage cable white spot detection method provided by an embodiment of the present invention is shown in FIG. Figure 2 As shown, the high-voltage cable white spot detection method includes:

[0038] S201. Obtain structural parameters of each layer of the cable external structure.

[0039] Structural parameters include the inner and outer diameters of the external structure, as well as thermal conductivity, etc.

[0040] S202. Establish a circular thermal path model of the cable according to the structural parameters.

[0041] The circular thermal path model is a cross section of the cable, and the cross section is divided into a plurality of sector-shaped microelements, each of which includes a plurality of thermal resistance branches extending from the conductor to the outer sheath. Each thermal resistance branch includes a structural thermal resistance corresponding to the external structure one by one; at least one thermal resistance branch also includes a white spot thermal resistance.

[0042] Figure 3is a schematic diagram of a circular heat path model. In an optional example, Figure 3 As shown, the circular thermal circuit model is the cross section of the cable, which is a circle and three rings from the inside to the outside, and the conductor A0, the insulation layer A1, the buffer layer A2 and the outer sheath A2 from the inside to the outside. The cross section is divided into multiple sector-shaped micro-elements. In this example, the number of sector-shaped micro-elements is 4 and the arc of each sector-shaped micro-element is the same, that is, the arc is π / 2. In the four thermal resistance branches, each thermal resistance branch includes 3 structural thermal resistances corresponding to the insulation layer A1, the buffer layer A2 and the outer sheath A2. In one of the thermal resistance branches, a white spot thermal resistance To is also included. The outer sheath A2 in this example is a smooth aluminum sheath.

[0043] In an alternative example, Figure 3 As shown, the number of sector elements is 4, the arc θ of each sector element is π / 2, and the thermal resistance branch corresponding to the first sector element includes the structural thermal resistance T 11 , T 12 , T 13 ; The thermal resistance branch corresponding to the second sector element includes the structural thermal resistance T 21 , T 22 , T 23 ; The thermal resistance branch corresponding to the third sector element includes the structural thermal resistance T 31 , T 32 , T 33 ; The thermal resistance branch corresponding to the fourth sector element includes the structural thermal resistance T 41 , T 42 , T 43 , and also includes white spot thermal resistance To; the white spot thermal resistance To is a preset virtual thermal resistance, that is, it is assumed that there is a white spot at this position and the white spot thermal resistance is To.

[0044] S203 . For each thermal resistance branch, calculate the thermal resistance value of the structural thermal resistance on each thermal resistance branch according to the curvature and structural parameters of the corresponding sector-shaped microelement.

[0045] Specifically, the calculation formula of the thermal resistance value of the structural thermal resistor on each thermal resistance branch is as follows:

[0046]

[0047] Wherein, i is the serial number of the sector element to which the thermal resistance branch belongs, i=1, 2...N s , N s is the number of the fan-shaped micro-element; j is the number of layers of the external structure in the fan-shaped micro-element, j = 1, 2 ... 3, λ i is the thermal conductivity, θ is the arc of the sector element, r jw is the outer diameter of the outer structure of the jth layer, r jnis the inner diameter of the outer structure of the jth layer, T ij is the thermal resistance value of the structural thermal resistance corresponding to the j-th layer of the external structure in the ith sector element.

[0048] In an alternative example, Figure 3 As shown, the number of sector elements is 4, and the arc θ of each sector element is π / 2.

[0049] S204, measuring the cable surface temperature, the conductor temperature of the conductor, and the load current value of the conductor corresponding to each thermal resistance branch.

[0050] In an optional embodiment, the temperature (cable surface temperature, conductor temperature of the conductor) is measured by a temperature sensor. Before measuring the cable surface temperature, conductor temperature and conductor load current value corresponding to each thermal resistance branch, it also includes: obtaining the reading deviation of the temperature sensor; judging whether the reading deviation of the temperature sensor is less than the preset deviation range; if so, executing the step of measuring the cable surface temperature, conductor temperature and conductor load current value corresponding to each thermal resistance branch. In order to ensure the accuracy of the temperature sensor measurement data, before using the sensor, connect the temperature sensor to the same experimental instrument to observe whether the reading has deviations and the specific reading deviations. Replace the temperature sensor with large deviations in time to reduce detection errors.

[0051] Specifically, the cable surface temperatures corresponding to the four thermal resistance branches can be directly measured, such as Figure 3 In the circular thermal circuit model shown in the figure, the corresponding surface temperatures of the four thermal resistance branches are measured as θ1, θ2, θ3, and θ4. The conductor temperature of the conductor needs to be measured by drilling holes along the trough of the aluminum sheath to the conductor using an electric drill, and the conductor temperature θ is detected by a temperature sensor. c ;The load current value of the conductor can be measured by contacting the current sensor.

[0052] S205. Calculate the heat flow of the entire cable according to the conductor temperature and load current value.

[0053] The calculation formula of the heat flow of the entire cable is as follows:

[0054] Q=I 2 R;

[0055] R=R0[1+α 20 (θ c -20)][1+y s +y p ];

[0056] Wherein, Q is the heat flow of the entire cable, I is the load current value, R is the AC resistance value of the conductor, R0, α 20is the DC resistance and temperature coefficient of the conductor at 20°C, θ c is the conductor temperature, y s ,y p These are the known skin effect factor and proximity effect factor.

[0057] The standard soft copper temperature coefficient is 0.00392K. The cable in the present invention is a single-core cable, that is, the number of conductors is 1. For the single-core cable, the proximity effect factor is 0.

[0058] S206. Calculate the thermal resistance value of the white spot thermal resistance based on the thermal resistance value of the structural thermal resistance, the cable surface temperature, the conductor temperature and the heat flow of the entire cable.

[0059] Specifically, the thermal resistance value of the white spot thermal resistance is calculated according to the thermal resistance value of the structural thermal resistance, the cable surface temperature, the conductor temperature and the heat flow of the entire cable, including:

[0060] A linear matrix formula is constructed based on Fourier's heat transfer law and the circular thermal circuit model, wherein the linear matrix formula includes the structural thermal resistance, the cable surface temperature, the conductor temperature, the conductor temperature, the heat flow of the entire cable and the white spot thermal resistance; the thermal resistance value of the white spot thermal resistance is obtained by substituting the numerical values ​​of the structural thermal resistance, the cable surface temperature, the conductor temperature, the conductor temperature and the heat flow of the entire cable into the linear matrix formula.

[0061] Fourier's heat transfer law, also known as Fourier's law, describes that during the heat conduction process, the amount of heat passing through a given cross section per unit time is proportional to the rate of temperature change and the cross-sectional area in the direction perpendicular to the cross section, and the direction of heat transfer is opposite to the direction of temperature increase.

[0062] In an optional embodiment, in Figure 3 In the circular thermal circuit model shown, the white spot thermal resistance is set on the fourth thermal resistance branch, and the established linear matrix formula is:

[0063]

[0064] Wherein, i is the serial number of the sector element to which the thermal resistance branch belongs, i=1, 2...N s , N s is the number of the fan-shaped micro-element; j is the number of layers of the external structure in the fan-shaped micro-element, j = 1, 2, 3, λ i is the thermal conductivity, θ is the arc of the sector element, r jw is the outer diameter of the outer structure of the jth layer, r jn is the inner diameter of the outer structure of the jth layer, T ijis the thermal resistance value of the structural thermal resistance corresponding to the j-th layer of the external structure in the ith sector-shaped microelement, and T0 is the thermal resistance value of the white spot thermal resistance.

[0065] Of course, the white spot thermal resistor can also be set on other thermal resistance branches. In an optional embodiment, the white spot thermal resistor is set on the third thermal resistance branch. Figure 3 In the circular thermal circuit model shown in Figure 1, the linear matrix formula established is:

[0066]

[0067] In another optional embodiment, if the number of sector-shaped micro-elements is 5, the arc of each sector-shaped micro-element is 2π / 5, and the white spot thermal resistance is set on the 3rd and 5th thermal resistance branches, it can be deduced based on the process of constructing the circular thermal path model and the linear matrix formula in the above text that the established linear matrix formula is:

[0068]

[0069] In an optional embodiment, the calculation formula of the heat flow of the entire cable is as follows:

[0070]

[0071] R=R0[1+α 20 (θ c -20)][1+y s +y p ];

[0072] Where Q is the heat flow of the entire cable, I l is the current carrying capacity of the conductor, R is the AC resistance of the conductor, R0, α 20 is the DC resistance and temperature coefficient of the conductor at 20°C, θ c is the conductor temperature, y s ,y p These are the known skin effect factor and proximity effect factor.

[0073] Among them, the current carrying capacity I l is the maximum current that the conductor can carry continuously and stably at 90°C. The conductor temperature at this time is θ c is 90°C. In this embodiment, the conductor temperature θ can be directly obtained c , there is no need to drill a hole from the cable surface to the conductor surface to detect the conductor temperature, thus achieving non-destructive detection of white spot thermal resistance.

[0074] The standard soft copper temperature coefficient is 0.00392K. The cable in the present invention is a single-core cable, that is, the number of conductors is 1. For the single-core cable, the proximity effect factor is 0.

[0075] S207, determining whether white spots exist and the location of white spots when white spots exist according to the thermal resistance value of the white spot thermal resistance.

[0076] Specifically, determine whether the thermal resistance value of the white spot thermal resistor is greater than 0; if not, determine that there is no white spot; if so, determine that there is a white spot; and take the sector-shaped microelement where the white spot thermal resistor is located as the location of the white spot.

[0077] That is, the hypothetical principle is adopted. It is first assumed that there is white spot thermal resistance in the insulation layer on a certain thermal resistance branch. If the calculated white spot thermal resistance is 0, it means that the white spot thermal resistance does not exist. If the calculated white spot thermal resistance is not 0 (greater than 0), it means that the white spot thermal resistance does exist, and it is assumed that the insulation layer corresponding to the thermal resistance branch where the white spot thermal resistance is located is the location where the white spot failure occurs.

[0078] The method further comprises: when white spots exist, calculating the thickness of the white spots according to the thermal resistance value of the white spot thermal resistor. The thermal resistance value of the white spot thermal resistor is proportional to the thickness of the white spot. The greater the white spot thermal resistance value, the greater the white spot thickness.

[0079] The method for detecting white spots in high-voltage cables provided by an embodiment of the present invention first obtains the structural parameters of the external structure of each layer of the cable, the structural parameters including the inner diameter and the outer diameter of the external structure; a circular thermal circuit model of the cable is established according to the structural parameters, the circular thermal circuit model is the cross section of the cable, the cross section is divided into a plurality of sector-shaped microelements, each sector-shaped microelement includes a plurality of thermal resistance branches extending from the conductor to the outer sheath, each thermal resistance branch includes a structural thermal resistance corresponding to the external structure one by one; at least one thermal resistance branch also includes a white spot thermal resistance; for each thermal resistance branch, the thermal resistance value of the structural thermal resistance on each thermal resistance branch is calculated according to the curvature and structural parameters of the sector-shaped microelement to which it belongs; the cable surface temperature, the conductor temperature of the conductor and the load current value of the conductor corresponding to each thermal resistance branch are measured; the heat flow of the entire cable is calculated according to the conductor temperature and the load current value, and the thermal resistance value of the white spot thermal resistance is calculated according to the thermal resistance value of the structural thermal resistance, the cable surface temperature, the conductor temperature and the heat flow of the entire cable; and whether white spots exist and the location of the white spots when white spots exist are determined according to the thermal resistance value of the white spot thermal resistance. Based on the thermal circuit model, the sector-shaped micro-element where the white spot is located is virtually constructed, and the parameters in each sector-shaped micro-element are measured and calculated. The thermal resistance value of the white spot is qualitatively calculated according to the Fourier heat transfer law combined with the thermal circuit model. Therefore, it is possible to determine whether there are white spots and the location of the white spots when they exist. The white spots can be detected in the early stage of their occurrence, and the filling of repair fluid can be used to repair the cable in time to prevent the white spots from further expanding and causing a greater impact on the cable's operating performance.

[0080] Corresponding to the high-voltage cable white spot detection method in the present invention, the embodiment of the present invention also provides a high-voltage cable white spot detection device. The cable structure includes a conductor and a three-layer external structure, the external structure includes an insulating layer, a buffer layer and an outer sheath from the inside to the outside, and the cross-section of the external structure is annular. Figure 4 This is a schematic diagram of the structure of a high-voltage cable white spot detection device provided in Embodiment 3 of the present invention. Figure 4 As shown, the high-voltage cable white spot detection device comprises:

[0081] A structural parameter acquisition module 401, used to acquire structural parameters of the external structure of each layer of the cable, wherein the structural parameters include the inner diameter and the outer diameter of the external structure;

[0082] A thermal circuit model building module 402 is used to establish a circular thermal circuit model of the cable according to the structural parameters, wherein the circular thermal circuit model is a cross section of the cable, wherein the cross section is divided into a plurality of sector-shaped micro-elements, each of which includes a plurality of thermal resistance branches extending from the conductor to the outer sheath, each of which includes a structural thermal resistance corresponding to the external structure one by one; and at least one of the thermal resistance branches also includes a white spot thermal resistance;

[0083] The thermal resistance value calculation module 403 is used to calculate the thermal resistance value of the structural thermal resistor on each thermal resistance branch according to the curvature of the sector-shaped microelement and the structural parameters.

[0084] The parameter measurement module 404 is used to measure the cable surface temperature, the conductor temperature and the load current value of the conductor corresponding to each thermal resistance branch;

[0085] The cable full-line heat flow calculation module 405 is used to calculate the cable full-line heat flow according to the conductor temperature and the load current value;

[0086] White spot thermal resistance calculation module 406, used to calculate the thermal resistance value of the white spot thermal resistance according to the thermal resistance value of the structural thermal resistance, the cable surface temperature, the conductor temperature and the heat flow of the entire cable;

[0087] The white spot qualitative module 407 is used to determine whether white spots exist and the location of the white spots when white spots exist according to the thermal resistance value of the white spot thermal resistance.

[0088] Optionally, the temperature is measured by a temperature sensor, and the high-voltage cable white spot detection device further includes:

[0089] A reading deviation acquisition module, used to acquire the reading deviation of the temperature sensor;

[0090] The deviation judgment module is used to judge whether the reading deviation of the temperature sensor is less than a preset deviation range; if so, the content of the parameter measurement module 404 is executed.

[0091] Optionally, the white spot thermal resistance calculation module 406 includes:

[0092] A linear matrix formula construction submodule, for constructing a calculation linear matrix formula based on Fourier's heat transfer law and the circular heat path model, wherein the linear matrix formula includes the structural thermal resistance, the cable surface temperature, the conductor temperature, the conductor temperature, the heat flow of the entire cable, and the white spot thermal resistance;

[0093] The white spot thermal resistance calculation submodule is used to substitute the numerical values ​​of the structural thermal resistance, the cable surface temperature, the conductor temperature, the conductor temperature, and the heat flow of the entire cable into the linear matrix formula to obtain the thermal resistance value of the white spot thermal resistance.

[0094] Optionally, the white spot qualitative module 407 includes:

[0095] A thermal resistance judgment submodule is used to judge whether the thermal resistance value of the white spot thermal resistance is greater than 0;

[0096] A first qualitative submodule is used to determine that there are no white spots if the thermal resistance value of the white spot thermal resistance is 0;

[0097] A second qualitative submodule is used to determine the presence of white spots if the thermal resistance value of the white spot thermal resistance is greater than 0;

[0098] The sector-shaped microelement where the white spot thermal resistance is located is taken as the location of the white spot.

[0099] Optionally, the high-voltage cable white spot detection device further includes:

[0100] The thickness detection module is used to calculate the thickness of the white spot according to the thermal resistance value of the white spot thermal resistor when the white spot exists.

[0101] The high-voltage cable white spot detection device provided in the embodiment of the present invention can execute the high-voltage cable white spot detection method provided in any embodiment of the present invention, and has the corresponding functional modules and beneficial effects of the execution method.

[0102] Figure 5 A schematic diagram of an electronic device 40 that can be used to implement an embodiment of the present invention is shown. The electronic device is intended to represent various forms of digital computers, such as laptop computers, desktop computers, workstations, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. The electronic device can also represent various forms of mobile devices, such as personal digital processing, cellular phones, smart phones, and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely examples and are not intended to limit the implementation of the present invention described and / or required herein.

[0103] like Figure 5 As shown, the electronic device 40 includes at least one processor 41, and a memory connected to the at least one processor 41, such as a read-only memory (ROM) 42, a random access memory (RAM) 43, etc., wherein the memory stores a computer program that can be executed by at least one processor, and the processor 41 can perform various appropriate actions and processes according to the computer program stored in the read-only memory (ROM) 42 or the computer program loaded from the storage unit 48 to the random access memory (RAM) 43. In the RAM 43, various programs and data required for the operation of the electronic device 40 can also be stored. The processor 41, the ROM 42, and the RAM 43 are connected to each other through a bus 44. An input / output (I / O) interface 45 is also connected to the bus 44.

[0104] A number of components in the electronic device 40 are connected to the I / O interface 45, including: an input unit 46, such as a keyboard, a mouse, etc.; an output unit 47, such as various types of displays, speakers, etc.; a storage unit 48, such as a disk, an optical disk, etc.; and a communication unit 49, such as a network card, a modem, a wireless communication transceiver, etc. The communication unit 49 allows the electronic device 40 to exchange information / data with other devices through a computer network such as the Internet and / or various telecommunication networks.

[0105] The processor 41 may be a variety of general and / or special processing components with processing and computing capabilities. Some examples of the processor 41 include, but are not limited to, a central processing unit (CPU), a graphics processing unit (GPU), various special artificial intelligence (AI) computing chips, various processors running machine learning model algorithms, a digital signal processor (DSP), and any appropriate processor, controller, microcontroller, etc. The processor 41 executes the various methods and processes described above, such as a high-voltage cable white spot detection method.

[0106] In some embodiments, the high-voltage cable white spot detection method can be implemented as a computer program, which is tangibly contained in a computer-readable storage medium, such as a storage unit 48. In some embodiments, part or all of the computer program can be loaded and / or installed on the electronic device 40 via the ROM 42 and / or the communication unit 49. When the computer program is loaded into the RAM 43 and executed by the processor 41, one or more steps of the high-voltage cable white spot detection method described above can be performed. Alternatively, in other embodiments, the processor 41 can be configured to perform the high-voltage cable white spot detection method in any other appropriate manner (for example, by means of firmware).

[0107] Various implementations of the systems and techniques described above herein can be implemented in digital electronic circuit systems, integrated circuit systems, field programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), application specific standard products (ASSPs), systems on chips (SOCs), complex programmable logic devices (CPLDs), computer hardware, firmware, software, and / or combinations thereof. These various implementations can include: being implemented in one or more computer programs that can be executed and / or interpreted on a programmable system including at least one programmable processor, which can be a special purpose or general purpose programmable processor that can receive data and instructions from a storage system, at least one input device, and at least one output device, and transmit data and instructions to the storage system, the at least one input device, and the at least one output device.

[0108] Computer programs for implementing the methods of the present invention may be written in any combination of one or more programming languages. These computer programs may be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device, so that when the computer program is executed by the processor, the functions / operations specified in the flow chart and / or block diagram are implemented. The computer program may be executed entirely on the machine, partially on the machine, partially on the machine and partially on a remote machine as a stand-alone software package, or entirely on a remote machine or server.

[0109] In the context of the present invention, a computer-readable storage medium may be a tangible medium that may contain or store a computer program for use by or in combination with an instruction execution system, device or equipment. A computer-readable storage medium may include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, devices or equipment, or any suitable combination of the foregoing. Alternatively, a computer-readable storage medium may be a machine-readable signal medium. A more specific example of a machine-readable storage medium may include an electrical connection based on one or more lines, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0110] To provide interaction with a user, the systems and techniques described herein may be implemented on an electronic device having: a display device (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor) for displaying information to the user; and a keyboard and a pointing device (e.g., a mouse or trackball) through which the user can provide input to the electronic device. Other types of devices may also be used to provide interaction with the user; for example, the feedback provided to the user may be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user may be received in any form (including acoustic input, voice input, or tactile input).

[0111] The systems and techniques described herein may be implemented in a computing system that includes backend components (e.g., as a data server), or a computing system that includes middleware components (e.g., an application server), or a computing system that includes frontend components (e.g., a user computer with a graphical user interface or a web browser through which a user can interact with implementations of the systems and techniques described herein), or a computing system that includes any combination of such backend components, middleware components, or frontend components. The components of the system may be interconnected by any form or medium of digital data communication (e.g., a communication network). Examples of communication networks include: a local area network (LAN), a wide area network (WAN), a blockchain network, and the Internet.

[0112] A computing system may include a client and a server. The client and the server are generally remote from each other and usually interact through a communication network. The client and server relationship is generated by computer programs running on the corresponding computers and having a client-server relationship with each other. The server may be a cloud server, also known as a cloud computing server or cloud host, which is a host product in the cloud computing service system to solve the defects of difficult management and weak business scalability in traditional physical hosts and VPS services.

[0113] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the present invention can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solution of the present invention can be achieved, and this document does not limit this.

[0114] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for detecting white spots on high-voltage cables, characterized in that: The structure of the cable includes a conductor and a three-layer external structure, the external structure includes an insulating layer, a buffer layer and an outer sheath from the inside to the outside, and the cross-section of the external structure is annular. The method includes: Acquire structural parameters of the external structure of each layer of the cable, wherein the structural parameters include the inner diameter and the outer diameter of the external structure; A circular thermal circuit model of the cable is established according to the structural parameters, wherein the circular thermal circuit model is a cross section of the cable, wherein the cross section is divided into a plurality of sector-shaped microelements, each of the sector-shaped microelements includes a plurality of thermal resistance branches extending from the conductor to the outer sheath, each of the thermal resistance branches includes a structural thermal resistance corresponding to the external structure one by one; at least one of the thermal resistance branches also includes a white spot thermal resistance; For each of the thermal resistance branches, the thermal resistance value of the structural thermal resistor on each of the thermal resistance branches is calculated according to the curvature of the sector-shaped microelement and the structural parameters; Measuring the cable surface temperature, the conductor temperature of the conductor and the load current value of the conductor corresponding to each of the thermal resistance branches; Calculate the heat flow of the entire cable according to the conductor temperature and the load current value; Calculate the thermal resistance value of the white spot thermal resistance according to the thermal resistance value of the structural thermal resistance, the cable surface temperature, the conductor temperature and the heat flow of the entire cable; Whether there are white spots and the location of the white spots when there are white spots are determined according to the thermal resistance value of the white spot thermal resistance.

2. The method for detecting white spots on high-voltage cables according to claim 1, characterized in that: The calculation formula of the thermal resistance value of the structural thermal resistor on each thermal resistor branch is as follows: Wherein, i is the serial number of the sector element to which the thermal resistance branch belongs, i=1, 2...N s , N s is the number of the fan-shaped micro-element; j is the number of layers of the external structure in the fan-shaped micro-element, j = 1, 2, 3, λ i is the thermal conductivity, θ is the arc of the sector element, r jw is the outer diameter of the outer structure of the jth layer, r jn is the inner diameter of the outer structure of the jth layer, T ij is the thermal resistance value of the structural thermal resistance corresponding to the j-th layer of the external structure in the ith sector element.

3. The method for detecting white spots on high-voltage cables according to claim 1, characterized in that: The temperature is measured by a temperature sensor. Before measuring the cable surface temperature, the conductor temperature of the conductor and the load current value of the conductor corresponding to each thermal resistance branch, the method further includes: Get the reading deviation of the temperature sensor; Determining whether the reading deviation of the temperature sensor is less than a preset deviation range; If so, the step of measuring the cable surface temperature, the conductor temperature of the conductor, and the load current value of the conductor corresponding to each of the thermal resistance branches is performed.

4. The method for detecting white spots on high-voltage cables according to claim 1, characterized in that: The calculation formula of the heat flow of the entire cable is as follows: Q=I 2 R; R=R0[1+α 20 (θ c -20)][1+y s +y p ]; Wherein, Q is the heat flow of the entire cable, I is the load current value, R is the AC resistance value of the conductor, R0, α 20 is the DC resistance and temperature coefficient of the conductor at 20°C, θ c is the conductor temperature, y s ,y p These are the known skin effect factor and proximity effect factor.

5. The method for detecting white spots on high-voltage cables according to claim 1, characterized in that: The thermal resistance value of the white spot thermal resistance is calculated according to the thermal resistance value of the structural thermal resistance, the cable surface temperature, the conductor temperature and the heat flow of the entire cable, including: Based on the Fourier heat transfer law and the circular heat path model, a linear matrix formula is constructed for calculation, wherein the linear matrix formula includes the structural thermal resistance, the cable surface temperature, the conductor temperature, the conductor temperature, the heat flow of the entire cable, and the white spot thermal resistance; The thermal resistance value of the white spot thermal resistance is obtained by substituting the numerical values ​​of the structural thermal resistance, the cable surface temperature, the conductor temperature, and the heat flow of the entire cable into the linear matrix formula.

6. The method for detecting white spots on high-voltage cables according to claim 1, characterized in that: The determining whether there is a white spot and the location of the white spot when the white spot exists according to the thermal resistance value of the white spot thermal resistance comprises: Determine whether the thermal resistance value of the white spot thermal resistance is greater than 0; If not, make sure that white spots are not present; If so, it is confirmed that white spots are present; The sector-shaped microelement where the white spot thermal resistance is located is taken as the location of the white spot.

7. The method for detecting white spots on high-voltage cables according to any one of claims 1 to 6, characterized in that: Also includes: When white spots exist, the thickness of the white spots is calculated according to the thermal resistance value of the white spot thermal resistance.

8. A high voltage cable white spot detection device, characterized in that: The structure of the cable includes a conductor and a three-layer external structure, the external structure includes an insulating layer, a buffer layer and an outer sheath from the inside to the outside, the cross section of the external structure is annular, and the device includes: A structural parameter acquisition module, used to acquire structural parameters of the external structure of each layer of the cable, wherein the structural parameters include the inner diameter and the outer diameter of the external structure; A thermal circuit model building module is used to establish a circular thermal circuit model of the cable according to the structural parameters, wherein the circular thermal circuit model is a cross section of the cable, wherein the cross section is divided into a plurality of sector-shaped micro-elements, each of which includes a plurality of thermal resistance branches extending from the conductor to the outer sheath, each of which includes a structural thermal resistance corresponding to the external structure one by one; and at least one of the thermal resistance branches also includes a white spot thermal resistance; A thermal resistance value calculation module, used for calculating the thermal resistance value of the structural thermal resistor on each thermal resistance branch according to the curvature of the sector-shaped microelement and the structural parameters thereof for each thermal resistance branch; A parameter measurement module, used to measure the cable surface temperature, the conductor temperature and the load current value of the conductor corresponding to each thermal resistance branch; A cable full-line heat flow calculation module, used to calculate the cable full-line heat flow according to the conductor temperature and the load current value; A white spot thermal resistance calculation module, used to calculate the thermal resistance value of the white spot thermal resistance according to the thermal resistance value of the structural thermal resistance, the cable surface temperature, the conductor temperature and the heat flow of the entire cable; The white spot qualitative module is used to determine whether white spots exist and the location of the white spots when white spots exist according to the thermal resistance value of the white spot thermal resistance.

9. An electronic device, characterized in that: The electronic device comprises: at least one processor; and a memory communicatively connected to the at least one processor; wherein, The memory stores a computer program executable by the at least one processor, and the computer program is executed by the at least one processor so that the at least one processor can execute the high-voltage cable white spot detection method according to any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer instructions, and the computer instructions are used to enable a processor to implement the high-voltage cable white spot detection method according to any one of claims 1 to 7 when executed.

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